Subject: [PWE3] draft-ietf-pwe3-vccv-bfd-00

From: "roman krzanwski" <[email-masked]>
Date: Tue, 8 Jan 2008 07:26:34 -0500

Adding BFD to VCCV channel will potentially create a large number of BFD
sessions what in addition to BFD sessions on interfaces and others may be
difficult to realize in real settings. Did you consider in your draft
implementation of mechanisms that would provide the similar function but at
the lower level of resource utilization ? For example, could we consider BFD
registered not to PW but to Group ID ( for REF 128), with one BFD session
serving one Group ID. Such BFD session would monitor the status of, lets
say, all PWs feeding to one  interface  or whatever construct the group id
is assigned to ?

rmk

Message: 3
Date: Mon, 07 Jan 2008 12:45:39 +0000
From: Stewart Bryant <[email-masked]>
Subject: [PWE3] draft-ietf-pwe3-vccv-bfd-00  - Last Call
To: pwe3 <[email-masked]>
Cc: Danny McPherson <[email-masked]>
Message-ID: <[email-masked]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

This is the start of last call on draft-ietf-pwe3-vccv-bfd-00

The draft can be found at:

http://tools.ietf.org/html/draft-ietf-pwe3-vccv-bfd-00

Last call will end Tues 22 Jan 2008

Please review this draft.

Thanks

Stewart
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From: Carlos Pignataro <[email-masked]>
Date: Fri, 18 Jan 2008 23:42:13 -0500

Roman,

Thank you for the comment, please see inline.

On 1/8/2008 7:26 AM, roman krzanwski said the following:
> sessions what in addition to BFD sessions on interfaces and others may 
> be difficult to realize in real settings. Did you consider in your draft
> implementation of mechanisms that would provide the similar function but 
> at the lower level of resource utilization ? For example, could we 
> consider BFD registered not to PW but to Group ID ( for REF 128), with 

This draft uses the PW Control Channel specified in RFC 5085 to use BFD 
for connectivity verification (as another Control Channel "payload"). 
 From RFC 5085, the PW VCCV Control Channel is associated with a single 
Pseudowire.
Another consideration is that the VCCV Capabilities are per-PW endpoint, 
so getting the minimal-set of the CV Capabilities would be much more 
challenging. One further issue is that the Group ID does not need to 
match in both directions, so the set of PWs with group ID of X in a 
local router does not necesarily equate the set of PWs with group ID of 
Y in the remote router, nor PWs with the same Group ID need to terminate 
in the same remote router.

> one BFD session serving one Group ID. Such BFD session would monitor the 
> status of, lets say, all PWs feeding to one  interface  or whatever 
> construct the group id is assigned to ?

The Group ID logically groups PWs, but seems more useful as a 
control-plane construct to send "wildcard" withdrawals / status 
messages, etc. In this case, would BFD exercise the data plane of a 
single PW in the Group ID (though other PWs can take different path) or 
round-robin (though a single PW down could bring the "Group ID" down)? 
In addition, I think it would much complicate the pwe3-oam-msg-map 
procedures.

Thanks,

--Carlos.

> From: Stewart Bryant <[email-masked] <mailto:[email-masked]>>
> To: pwe3 <[email-masked] <mailto:[email-masked]>>
> Cc: Danny McPherson <[email-masked] <mailto:[email-masked]>>
> Message-ID: <[email-masked] <mailto:[email-masked]>>
> ------------------------------------------------------------------------
> 

-- 
--Carlos Pignataro.
Escalation RTP - cisco Systems